mirror of
https://github.com/zebrajr/react.git
synced 2025-12-06 00:20:04 +01:00
A declarative, efficient, and flexible JavaScript library for building user interfaces.
reactjs.org
c4a3b92e09
Stacked on #32585 and #32605. This adds more loops for the phases of "Apply Gesture". It doesn't implement the interesting bit yet like adding view-transition-names and measurements. I'll do that in a separate PR to keep reviewing easier. The three phases of this approach is roughly: - Clone and apply names to the "old" state. - Inside startViewTransition: Apply names to the "new" state. Measure both the "old" and "new" state to know whether to cancel some of them. Delete the clones which will include all the "old" names. - After startViewTransition: Restore "new" names back to no view-transition-name. Since we don't have any other Effects in these phases we have a bit more flexibility and we can avoid extra phases that traverse the tree. I've tried to avoid any additional passes. An interesting consequence of this approach is that we could measure both the "old" and "new" state before `startViewTransition`. This would be more efficient because we wouldn't need to take View Transition snapshots of parts of the tree that won't actually animate. However, that would require an extra pass and force layout earlier. It would also have different semantics from the fire-and-forget View Transitions because we could optimize better which can be visible. It would also not account for any late mutations. So I decided to instead let the layout be computed by painting as usual and then measure both "old" and "new" inside the startViewTransition instead. Then canceling anything that doesn't animate to keep it consistent. Unfortunately, though there's not a lot of code sharing possible in these phases because the strategy is so different with the cloning and because the animation is performed in reverse. The "finishedWork" Fiber represents the "old" state and the "current" Fiber represents the "new" state. The most complicated phase is the cloning. I actually ended up having to make a very different pattern from the other phases and CommitWork in general. Because we have to clone as we go and also do other things like apply names and finding pairs, it has more phases. I ended up with an approach that uses three different loops. The outer one for updated trees, one for inserted trees that don't need cloning (doesn't include reappearing offscreen) and one for not updated trees that still need cloning. Inside each loop it can also be in different phases which I track with the `visitPhase` enum - this pattern is kind of new. Additionally, we need to measure the cloned nodes after we've applied mutations to them and we have to wait until the whole tree is inserted. We don't have a reference to these DOM elements in the Fiber tree since that still refers to the original ones. We need to store the cloned elements somewhere. So I added a temporary field on the ViewTransitionState to keep track of any clones owned by that ViewTransition. When we deep clone an unchanged subtree we don't have DOM element instances. It wouldn't be quite safe to try to find them from the tree structure. So we need to avoid the deep clones if we might need DOM elements. Therefore we keep traversing in the case where we need to find nested ViewTransition boundaries that are either potentially affected by layout or a "pair". For the other two phases the pattern there's a lot of code duplication since it's slightly different from the commit ones but they at least follow the same pattern. For the restore phase I was actually able to reuse most of the code. I don't love how much code this is. |
||
|---|---|---|
| .codesandbox | ||
| .github | ||
| compiler | ||
| fixtures | ||
| packages | ||
| scripts | ||
| .editorconfig | ||
| .eslintignore | ||
| .eslintrc.js | ||
| .git-blame-ignore-revs | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .nvmrc | ||
| .prettierignore | ||
| .prettierrc.js | ||
| .watchmanconfig | ||
| babel.config-react-compiler.js | ||
| babel.config-ts.js | ||
| babel.config.js | ||
| CHANGELOG-canary.md | ||
| CHANGELOG.md | ||
| CODE_OF_CONDUCT.md | ||
| CONTRIBUTING.md | ||
| dangerfile.js | ||
| LICENSE | ||
| MAINTAINERS | ||
| package.json | ||
| react.code-workspace | ||
| ReactVersions.js | ||
| README.md | ||
| SECURITY.md | ||
| yarn.lock | ||
React · 
React is a JavaScript library for building user interfaces.
- Declarative: React makes it painless to create interactive UIs. Design simple views for each state in your application, and React will efficiently update and render just the right components when your data changes. Declarative views make your code more predictable, simpler to understand, and easier to debug.
- Component-Based: Build encapsulated components that manage their own state, then compose them to make complex UIs. Since component logic is written in JavaScript instead of templates, you can easily pass rich data through your app and keep the state out of the DOM.
- Learn Once, Write Anywhere: We don't make assumptions about the rest of your technology stack, so you can develop new features in React without rewriting existing code. React can also render on the server using Node and power mobile apps using React Native.
Learn how to use React in your project.
Installation
React has been designed for gradual adoption from the start, and you can use as little or as much React as you need:
- Use Quick Start to get a taste of React.
- Add React to an Existing Project to use as little or as much React as you need.
- Create a New React App if you're looking for a powerful JavaScript toolchain.
Documentation
You can find the React documentation on the website.
Check out the Getting Started page for a quick overview.
The documentation is divided into several sections:
- Quick Start
- Tutorial
- Thinking in React
- Installation
- Describing the UI
- Adding Interactivity
- Managing State
- Advanced Guides
- API Reference
- Where to Get Support
- Contributing Guide
You can improve it by sending pull requests to this repository.
Examples
We have several examples on the website. Here is the first one to get you started:
import { createRoot } from 'react-dom/client';
function HelloMessage({ name }) {
return <div>Hello {name}</div>;
}
const root = createRoot(document.getElementById('container'));
root.render(<HelloMessage name="Taylor" />);
This example will render "Hello Taylor" into a container on the page.
You'll notice that we used an HTML-like syntax; we call it JSX. JSX is not required to use React, but it makes code more readable, and writing it feels like writing HTML.
Contributing
The main purpose of this repository is to continue evolving React core, making it faster and easier to use. Development of React happens in the open on GitHub, and we are grateful to the community for contributing bugfixes and improvements. Read below to learn how you can take part in improving React.
Code of Conduct
Facebook has adopted a Code of Conduct that we expect project participants to adhere to. Please read the full text so that you can understand what actions will and will not be tolerated.
Contributing Guide
Read our contributing guide to learn about our development process, how to propose bugfixes and improvements, and how to build and test your changes to React.
Good First Issues
To help you get your feet wet and get you familiar with our contribution process, we have a list of good first issues that contain bugs that have a relatively limited scope. This is a great place to get started.
License
React is MIT licensed.